Around 125 million years ago, the carcase of a pterosaur was washed into the mud at the bottom of a river. It lay there undisturbed until a few years ago, when coastal erosion removed it from its rocky tomb. Parts of the skull and wing bones were found on the beach by several different local collectors. Other parts may have been washed away already.
Pterosaurs were winged reptiles that lived at the same time as dinosaurs. The earliest pterosaurs are found in Triassic rocks in Italy, around 235 million years old. They survived until the end of the Cretaceous Period, by which point many large forms existed, with wingspans of over 12 metres. The reason for their extinction 65 million years ago is a mystery, but it was the end for many other animal and plant groups on Earth. The new pterosaur from Sandown Bay belongs to a family called the Ornithocheiridae (‘bird hand’). They are large pterosaurs with crested skulls, long pointed teeth, and wingspans of around 4-6 metres. Ornithocheirids have been found in Cretaceous rocks in many parts of the world, particularly the UK, Brazil and North Africa. The Sandown pterosaur is different from any that have been previously discovered, so it has been given a new name: Caulkicephalus trimicrodon. The generic name is derived from ‘caulkhead’, the traditional local name for people who caulked ships in the Solent shipyards. The species trimicrodon refers to the three small teeth near the front of the jaw. The bones, which include the braincase, upper jaw and wing bones, were found on Yaverland beach by G. Leng, T. Winch, D. Davies, M. New, M. Munt, and L. Steel. The new pterosaur is described in the latest issue of the scientific journal Cretaceous Research, by a scientific team including Dinosaur Isle Museum, University of Portsmouth and the Humboldt Museum in Berlin. The full reference is:
Steel, L., Martill, D. M., Unwin, D. M. & Winch, J. D. (2005) A new pterodactyloid pterosaur from the Wessex Formation (Lower Cretaceous) of the Isle of Wight, England. Cretaceous Research (2005): 1-13.
Skull reconstruction
Figure 1. A reconstruction of the skull of Caulkicephalus trimicrodon by Lorna Steel. The rostrum ('upper jaw') 
Figure 2. Palatal view of the rostrum of C. trimicrodon 
Figure 3. Right lateral view of the rostrum 
Figure 4. Drawing of the distal portion of the rostrum The two images shown in Figures 3 and 4 show the right lateral view of the rostrum (or upper part of the jaw). The rostrum is in three parts as can be seen in the photograph (Figure 2). The sockets for the teeth show that there are two prominent forward facing teeth at the snout, with three larger teeth behind on each side. Just to the left of the fracture (Figure 4) are sockets for three small teeth on each side. It is this feature that gives the species its name (trimicrodon = three-small-teeth). From this point back the teeth are staggered in alternate positions as can be seen in the palatal views below and in Figure 2. The preserved part of the rostrum is 29cm in length. 
Figure 5. Drawings of the palatal view of the rostrum.  Figure 6. Anterior view of the rostrum.
This view of the 'snout' shows the position of the forward facing tooth sockets (dental alveoli). The small black spot seen in one of the sockets is the tip of a replacement tooth. Figure 7. An unrelated pterosaur tooth shown for comparison.
The braincase  Figure 8. Posterior view of the partial braincase. Associated with the rostrum was a partial braincase which is assumed to come from the same individual. The image shows the back (posterior) view and the base of the skull crest. | 
